1. Field of the Invention
The present invention relates to semiconductor devices, and more particularly, to a semiconductor device and a method for fabricating the same, which prevents a decrease in the drain current of a metal-oxide-silicon transistor that is subject to short channel effects.
2. Discussion of the Related Art
A highly integrated semiconductor device includes a multitude of transistors formed on a semiconductor substrate, each having a finite channel length. Short channel effects, which destroy normal transistor operation as an electrical field is rapidly developed and applied to a channel region, are increasingly prevalent in more highly integrated semiconductor devices, which inherently have shorter channel lengths.
To prevent such deterioration of transistor characteristics, short channels effects should be minimized. Minimizing short channel effects may be achieved by performing an additional ion implantation step when forming a transistor having a lightly doped drain structure in which low-density source and drain regions are formed on either side of a gate before forming spacers on gate sidewalls. However, a decrease in the intensity of the electrical field, while minimizing the short channel effect, results in a rapid decrease in drain current.